• Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

DC motors!!!

Status
Not open for further replies.

maria

New Member
Hi guys :D ,
There is a question related to commutation problems of DC motor. As we all know, the major problem is the “armature reaction” i.e. a magnetic field is produced by the current flowing in the armature windings, which distorts the field of the poles. Its most hazardous effect is called “flux weakening”. I.e. the overall flux under the entire pole faces decreases.
Q : I want to know, when the load on machine is increased, how flux decreases??? What happens to the speed of armature???

And in some DC shunt motors, due to this flux weakening effect “Run away condition” is achieved at which speed goes on increasing until it is disconnected from the supply or it is destroyed.
Q : How this rum away condition is achieved???
maria
 

Phasor

Member
And in some DC shunt motors, due to this flux weakening effect “Run away condition” is achieved at which speed goes on increasing until it is disconnected from the supply or it is destroyed.
This is not a property of shunt motors, but actually of series motors. I'm a bit rusty with DC motors at the moment, so I can't say why this is, but I'll get back to you after I look it up in my texts...
 
Status
Not open for further replies.

Latest threads

EE World Online Articles

Loading
Top